Effects of Salinity on Chlorophyll Fluorescence and Photosynthesis of Barley (Hordeum Vulgare L.) Grown Under a Triple-Line-Source Sprinkler System in the Field |
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Authors: | Belkhodja R Morales F Abadía A Medrano H Abadía J |
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Institution: | (1) Laboratorio Asociado de Agronomía y Medio Ambiente (DGA-CSIC), Unidad de Suelos y Riegos, Servicio de Investigación Agroalimentaria (D.G.A.), Apartado 727, 50080 Zaragoza, Spain |
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Abstract: | In flag leaves of four cultivars of barley (Hordeum vulgare L.) grown in the field under a triple-line-source sprinkler system,
that produces a linear soil salinity gradient, a decrease in net carbon dioxide assimilation rate (PN) and stomatal conductance for water vapour (gs) was found. These changes were related to salinity tolerance at moderate salinity.
With increasing salinity, PN was saturated at low irradiances and stomatal frequencies increased. A decrease in photosystem 2 (PS2) efficiency was not
found in the field after dark adaptation even at high salinity. Salinity induced only small decreases in the actual PS2 efficiency
at midday steady-state photosynthesis, indicating that the photosynthetic electron transport was little affected by salinity.
Therefore, using PS2 efficiency estimates in attached leaves is probably not a useful tool to screen barley genotypes grown
under saline conditions in the field for salinity tolerance. In contrast, excised flag leaves from high salinity plots, once
in the laboratory, exhibited a decrease in the variable to maximum chlorophyll fluorescence ratio as compared to excised leaves
from control plants. On the other hand, the PN rate might allow for a good discrimination between tolerant and non-tolerant
cultivars.
This revised version was published online in June 2006 with corrections to the Cover Date. |
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Keywords: | chlorophyll fluorescence cultivar differences photosystem 2 efficiency stomatal conductance and frequency transpiration rate |
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